DATA1220-55, Fall 2024
2024-11-20
Which image shows a positive relationship between the explanatory and response variables?
Which image shows a strong relationship between the explanatory and response variables?
A correlation ranges from -1 to 1
A perfect negative correlation equals -1
A perfect positive correlation equals 1
What’s the response variable?
Response Variable: Percent of people in poverty
What’s the explanatory variable?
Explanatory variable: Percent of people who graduated high school
Describe the relationship between these 2 variables.
Relationship: linear, negative, moderate to strong
Which of the following is the most likely correlation? A. 0.60 B. -0.25 C. -0.75 D. 0.35
Which of the following is the most likely correlation? C. -0.75
\[ H_0 \colon \rho=0 \]
\[ \begin{aligned} H_A &\colon \rho > 0 \\ & \rho < 0 \\ & \rho \ne 0 \\ \end{aligned} \]
The test statistic \(t\) for the population Pearson correlation \(\rho\) (Greek letter rho) is estimated using the observed correlation \(r\).
\[ t=\frac{r\sqrt{n-2}}{\sqrt{1-r^2}} \]
Use the Student’s \(t\) distribution with degrees of freedom \(\text{df}=n-2\) to find a p-value for the observed correlation \(r\) in a sample of size \(n\) under the null hypothesis \(H_0 \colon \rho=0\).
How do we find the best line to draw through variables that appear to have a linear relationship?
Residuals are the difference between the observed values and the predicted values.
Do ice cream sales cause drowning incidents?
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DATA1220-55 Fall 2024, Class 31 | Updated: 2024-11-20 | Canvas | Campuswire